New York:

Larry Morgan of Duke Energy convened the P1159.2 Task Force meeting on Monday, February 1, 1999, at 14:30 in the Petit Trianon room of the Hilton Hotel in NYC. Twenty-three (23) members were present. The minutes of the Summer meeting were approved as posted on the www site. All Action Items from that meeting were completed or addressed and ongoing, though Erich is to re-send the document on relevant IEC standards to Larry. Nine written comments on the draft have received so far, and none from committee members. The status of the Annex sections were reviewed, with significant discussion on Annex A (characteristics). Annex C (what causes characteristics) is not started. The www site address is http://grouper.ieee.org/groups/1159/2/index.html. Larry Morgan's new e-mail address is rlmorgan@duke-energy.com

DISCUSSION

Formal comments from members are needed, using the www site. The document consists of both normative (thou shall) and informative (why thou shall). Seven additional details on point-on-wave have been added, such as point of initiation and point of recovery. Parameter types from this task force need to be included as tags in 1159.3's work. Using 5% and 10% bandwidths, a mag-dur table using missing voltage was demonstrated as a means to assist drive manufacturers to develop power supplies.

Concern was raised over how to deal with the situations, such as switching between transformers, where the recover has a "permanent" phase angle difference from the original source, and the impact on the missing voltage algorithm. Also, the effect of where the data was acquired (PCC vrs point of utilization) will have an effect that needs to be noted.

Annex C is to describe what phenomena result in such things as phase shift in sags. This annex has no work done yet. Dan Sabin is going to request the assistance of David Meuller of Electrotek on such.

(see response attached)

The goal is to have the draft ready for ballot by December 1, 1999.

The next meeting will be in Edmonton, at a to-be-announced date and time during the July meeting week.

• Erich Gunther of Electrotek is to resent relevant IEC standards.
• Arsheed Mansoor of PEAC as chapter chairperson on what elements effect what type of equipment (Annex B) -- work to be completed by summer meeting
• Dan Sabin of Electrotek as chapter chairperson on example test waveforms characterized (Annex E) -- work to be completed by summer meeting

WINTER MEETING ACTION ITEMS

• Dan Sabin to request David Meuller as Chairperson for sources of characterization (Annex C)
• Task force at large to provide comments on draft document, as well as submit additional relevant waveforms.
• Richard Bingham of Dranetz-BMI to produce minutes
• Larry Morgan of Duke Energy to post minutes on WWW site after his review.

As I understand, we wanted to keep it pretty non-technical.

Phase Angle Transition During Faults on Utility Systems

There are three basic phenomena that created phase angle transition in system voltages during faults on utility systems:

1. Connection of two voltages, that "pull together". When two phases short together, in a "bolted" condition their voltages must become identical, so "they pull together". Normally some fault impedance will allow for some voltage between them (due to fault current through this fault impedance) so that they will only "pull toward one another" and not completely become identical. A similar condition occurs, of course, when two lines go to ground.

2. Transformer sag shift is the name that I give to the effect that most transformer winding configurations have on voltage sags. It involves the majority of common connections, or more specifically those that break the zero sequence connection. The effect is that the zero sequence during the sag can not go through the winding connections. This causes phase angle transition even though there may be no phase angle transition on the faulted side of the transformer. It can be thought of as "shifting the unbalanced voltages, unevenly".

3. Effects from loads (motors). I would believe that this effect is very minor. For example, when motors see negative sequence voltage during voltage sags, they draw negative sequence currents which also affects the system voltages. Normally not very important to consider for phase angle transition.

--Dave Mueller

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